Tankless Domestic Hot Water Modes; Adding Domestic Hot Water Storage - IBC DC 23-84 Installation And Operating Instructions Manual

BOILER SYSTEMS AND OPERATION
DC SERIES COMBI BOILERS DC 23-84, DC 29-106, DC 33-124, DC 33-160
2.4 TANKLESS DOMESTIC HOT WATER
MODES
2.4.1 Tankless Domestic Hot Water - Standard,
Comfort and ECO Comfort Modes
Standard Mode (both LEDs are off): The boiler's heat exchanger will not
maintain its domestic hot water temperature between demands for hot water.
(This the most energy efficient mode but will result in the "Cold Water Sandwich
Effect".) The boiler will respond to a call for domestic hot water as a priority over
the space heating demand. When the domestic hot water demand is satisfied the
boiler will return to the space heating load if the load is still calling.
Comfort Mode (the top LED is on): The boiler's heat exchanger will maintain
the pre-programmed temperature set in parameter n. or as set for the Tankless
hot water temperature. (This is the least efficient mode but does offer the
most consistent hot water delivery temperatures). This temperature will be the
minimum temperature of the heat exchanger at all times unless the boiler is
heating a low temperature load.
ECO Comfort Mode (the bottom LED is on): This mode operates like the
Comfort Mode but has the added advantage of learning when the domestic hot
water is used. During the low use periods the boilers heat exchanger is allowed
to cool. (This mode is the most practical of the three options).
To toggle between the 3 modes simply press the Domestic Hot Water Comfort /
Eco button.
2.5 ADDING DOMESTIC HOT WATER
STORAGE
2.5.1 Tankless Domestic Hot Water with a Storage
Tank
The DC series boiler has the ability to connect a domestic hot water storage tank
to the boiler to prove larger volumes of domestic hot water during peak demands.
The storage tank will be piped to the boiler's domestic hot and cold water piping
connections (see Figure #30 on Page 1-29). A bronze or stainless steel pump
must be installed to circulate water from the storage tank through the boiler's
domestic hot water coil. The pump and the tank aquastat can be wired directly to
the boiler's control for ease of installation.
Alternately, the pump and aquastat can be wired together without connecting to
the boiler. When the pump is energized, the flow of water through the domestic
hot water coil in the boiler will be sensed by the flow sensor and activates the
boiler. The boiler will switch off its internal pump and operate at its programmed
water temperature set in parameter [1].
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